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crestavega · 15th Jul 2017, 11:32 am

Upon looking at the diagram with a clearer head, I can see that the -70V is likely "coming from" pin 10 of the power connector, which is stated -84V by design. I guess this is the grid bias, and must be kept fairly negative in order to check the electrons acceleration through the tube. (have I got this part of valve theory right?)

However, it seems odd that the test meter (which is a center zero dial) should be pegging hard left on the position 5 (Final Drive) setting. this at least doesnt seem right for a design. The meter is pegging negative because there is -70V across it in this position.

please help!

15th Jul 2017, 11:32 am	#41
crestavega Pentode Join Date: Apr 2014 Location: Kirkwall, Orkney, UK. Posts: 165	Re: Sailor T128 Marine Transmitter. Upon looking at the diagram with a clearer head, I can see that the -70V is likely "coming from" pin 10 of the power connector, which is stated -84V by design. I guess this is the grid bias, and must be kept fairly negative in order to check the electrons acceleration through the tube. (have I got this part of valve theory right?) However, it seems odd that the test meter (which is a center zero dial) should be pegging hard left on the position 5 (Final Drive) setting. this at least doesnt seem right for a design. The meter is pegging negative because there is -70V across it in this position. please help!